入门案例分析:
1.执行流程
1.当启动tomcat服务器时,由于配置了load_on_startup标签,所以会创建DispatcherServlet对象,就会加载springmvc.xml配置文件
2.开启了注解扫描,HelloController对象就会被创建
3.从index.jsp发送请求,请求会先到达DispatcherServlet核心控制器,根据配置@RequestMapping注解找到执行的具体方法
4.根据方法的返回值,再根据配置的视图解析器,去指定的目录下查找指定名称的jsp文件
5.Tomcat服务器渲染页面,做出响应
2.流程图
3.RequestMapping注解
1.RequestMapping注解的作用是建立请求URL和处理方法之间的对应关系
2.RequestMapping注解可以作用在方法和类上
作用在类上:第一级的访问目录
作用在方法上:第二级的访问目录
细节:/表示应用的根目录开始
${pageContext.request.contextPath}也可以省略不写,但是路径上不能写/
3.RequestMapping属性:
path:指定请求路径的url
value:同path一样
method:指定该方法的请求方式,是枚举类型
params:指定限制请求参数的条件
headers:发送的请求中必须包含的请求头
SpringMVC的入门程序案例
1.创建WEB工厂,引入开发的jar包,需要导入的坐标如下
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
<spring.version>5.0.2.RELEASE</spring.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
<version>2.0</version>
<scope>provided</scope>
</dependency>
</dependencies>
2.配置核心的控制器(DispatcherServlet)
在web.xml配置文件中
<web-app>
<display-name>Archetype Created Web Application</display-name>
<!--springMVC的核心控制器-->
<servlet>
<servlet-name>dispatcherServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<!--配置Servlet的初始化参数哦,读取springmvc的配置文件,创建spring容器-->
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:springMVC.xml</param-value>
</init-param>
<!--配置servlet启动时加载对象-->
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>dispatcherServlet</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
3.编写springmvc.xml配置文件
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd">
<!--开启注解扫描-->
<context:component-scan base-package="cn.ycl"></context:component-scan>
<!--视图解析器对象-->
<bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/pages/"/>
<property name="suffix" value=".jsp"/>
</bean>
<!--开启springMVC框架对注解的支持-->
<mvc:annotation-driven/>
</beans>
4.编写index.jsp和HelloController控制器类
1.index.jsp
<body>
<h3>入门程序</h3>
<a href="hello">入门程序</a>
</body>
2.HelloController
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
//控制器类
@Controller
public class HelloController {
@RequestMapping(path = "/hello")
public String sayHello(){
System.out.println("Hello,springMVC!!");
return "success";
}
}
5.在WEB-INF目录下创建pages文件夹,编写success.jsp的成功页面
<h3>返回成功</h3>
6.启动服务器进行测试